Drive chains and sprockets have long been used to transmit rotational motion and to provide timing between rotating members. Drive chains typically include a series of cylindrical rollers held together with links at each end of the rollers. The rollers engage sprocket teeth which extend radially outward from the sprocket. One problem associated with drive chains and sprockets is noise that may result from engagement of the drive chain and the sprocket during operation. In order to minimize noise, it is known to bond a cushion ring, made of a resilient and compliant material such as an elastomer, to each side of the sprocket. The links of the drive chain engage the cushion rings during operation, thereby reducing noise. While these known cushion rings may be effective at reducing noise and vibration, separation of the cushion ring from the sprocket is a known issue which results from the cushion rings being subjected to cyclical compression and relaxation during use.
U.S. Pat. No. 7,862,460 to Chekansky et al. illustrates prior art arrangements for retaining cushion rings on a sprocket. More specifically Chekansky et al. shows prior art arrangements where the cushion rings are located within an annular groove formed either by cutting the groove directly in the sprocket or by forming the groove with a stack of annular bodies. While the channel may provide some retention of the cushion rings in the axial direction, i.e. in the direction of the axis about which the sprocket rotates, the channel does not provide retention in the radial direction relative to the axis about which the sprocket rotates. Consequently, the cushion rings are still vulnerable to separation from the sprocket.
What is needed is a sprocket assembly which minimizes or eliminates one or more of the shortcomings as set forth above.